This invention relates to alignment of basket retainer clips for heat exchanger tube cleaning elements.
It is known from the above-identified patents to connect individual elongated cleaning element capturing cages or baskets to both ends of longitudinally extending tubes disposed in a heat exchanger housing. The tube ends are held in position at both ends by transverse tube sheets. The baskets are adapted to contain shuttleable cleaning elements such as brushes. Fluid flowing in one direction through the tubes keeps the cleaning elements captured within their respective basket chambers, while the fluid discharges outwardly through openings in the basket walls. Upon reversal of fluid flow, the cleaning elements are forced out of their baskets and through the tubes to the baskets at the opposite tube ends to thereby perform a tube cleaning action.
Many baskets are designed of plastic and with their elongated body portions formed by alternating ribs and fluid flow-through slots which terminate in an annular outer end ring. The inner edge portion of the ring is alternately joined to the ribs or exposed to form the outer slot ends. For purposes of retaining a cleaning element within the basket and yet allowing the cleaning element to be removed for more complete access to the tube interiors, a retainer has been removably attached to the outer basket end. One form of retainer has comprised a central body supporting a plurality of flexible clips which extend longitudinally inwardly. The clips are provided with end prongs and stop projections spaced therefrom. When the retainer is assembled onto the basket, the prongs snap into the slots and the stop projections engage the outer edge of the basket end ring to limit entry of the retainer into the basket.
The basket retainers are often formed of molded plastic, and with the clips having legs first extending longitudinally outwardly and then forming a reverse loop base portion with the legs being bent back upon themselves so that the legs extend longitudinally inwardly along the retainer central body. For proper functioning of the snap-in retainer, it is highly desirable that the clip legs are parallel to the said central body and to each other.
It has been found that upon release from the molding die, at least some of the clip legs tend to be collapsed radially inwardly from their base portions. When a retainer having freely collapsed clip legs is inserted into a basket, the prongs may not fully engage with the end edges of the slots.
It is a task of the invention to eliminate the clip leg collapse and assure that the legs are in general parallelism with the longitudinal retainer axis when they are inserted into the basket.
In accordance with the various aspects of the invention, a leg joining element is molded into the clip so that the legs are prevented from collapsing when the retainer is released from the die. More specifically, a radial rib means is formed at the base of the loop and joins the longitudinally outwardly and inwardly extending clip leg portions to spread the clip legs into parallelism with the retainer axis.